2. Example of shear-wave splitting applied to a set of SKS splitting measurements

This example shows how the code can be applied to undertake shear-wave splitting analysis on SKS data.

The data is from:

J Asplet, J Wookey, M Kendall. (2020) “A potential post-perovskite province in D″ beneath the Eastern Pacific: evidence from new analysis of discrepant SKS–SKKS shear-wave splitting”. GJI.

%load_ext autoreload
%autoreload 2

import swspy
import obspy
from obspy import UTCDateTime
import numpy as np
%matplotlib notebook
import matplotlib.pyplot as plt
import glob
import os, sys
import pandas as pd

2.1. 1. Get event information from auxiliary files (specific to this dataset):

# List event UIDs and station names:
datadir = os.path.join("data","splittingsample","data")
fnames_all_tmp = glob.glob(os.path.join(datadir, "*.BH*"))
event_uids = []
for fname_tmp in fnames_all_tmp:
    fname_no_path = os.path.split(fname_tmp)[-1]
    event_uids.append(fname_no_path.split(".")[0])

# Read in event window and back azimuth data:
aux_data_fname = os.path.join("data","splittingsample", "Sample_SKS_SKKS_data.sdb")
aux_data_df = pd.read_csv(aux_data_fname, delimiter=" ")

2.2. 2. Loop over events, doing shear-wave splitting processing:

# Loop over events:
for event_uid in event_uids:
    print("Processing for event:", event_uid)
    # Load data:
    mseed_path = os.path.join(datadir, event_uid)
    station = event_uid.split("_")[0]
    event_starttime = obspy.UTCDateTime(year=int(event_uid.split("_")[1][0:4]), julday=int(event_uid.split("_")[1][4:7]),
                                        hour=int(event_uid.split("_")[2][0:2]), minute=int(event_uid.split("_")[2][2:4]),
                                       second=int(event_uid.split("_")[2][4:6]))
    aux_data_df_row_idx = aux_data_df.index[aux_data_df["STAT"]==station].tolist()[0]
    win_starttime = event_starttime + aux_data_df["WBEG"][aux_data_df_row_idx] - 5
    win_endtime = event_starttime + aux_data_df["WEND"][aux_data_df_row_idx] +5

    s_pick_after_starttime = win_starttime+5
    downsample_factor = 1 #4 #5 #10 # Factor to downsample data by (for faster slitting)
    load_wfs_obj = swspy.io.load_waveforms(mseed_path, archive_vs_file="file", downsample_factor=downsample_factor)
    load_wfs_obj.filter = True
    load_wfs_obj.filter_freq_min_max = [0.01, 0.5]
    st = load_wfs_obj.read_waveform_data()

    # Calculate splitting:
    splitting_event = swspy.splitting.create_splitting_object(st, event_uid=event_uid, stations_in=[station], S_phase_arrival_times=[s_pick_after_starttime]) #(st, nonlinloc_event_path) #(st.select(station="ST01"), nonlinloc_event_path)
    splitting_event.overall_win_start_pre_fast_S_pick = 4.0 #0.1
    splitting_event.win_S_pick_tolerance = 1.0
    splitting_event.overall_win_start_post_fast_S_pick = (win_endtime - win_starttime) - 10 #0.2
    splitting_event.rotate_step_deg = 1.0 #2.5
    splitting_event.max_t_shift_s = 5.0
    splitting_event.n_win = 10 #5 #10
    # splitting_event.perform_sp
    splitting_event.perform_sws_analysis(coord_system="ZNE", sws_method="EV_and_XC") #(coord_system="LQT") #(coord_system="ZNE")

    # And plot splitting result:
    splitting_event.plot(outdir=os.path.join("outputs", "plots"))

    # And save result to file:
    splitting_event.save_result(outdir=os.path.join("outputs", "data"))

Processing for event: FACU_2009297_144044_SKS

/Users/eart0504/Documents/python/github_repositories/swspy/swspy/splitting/split.py:940: UserWarning: This figure was using constrained_layout==True, but that is incompatible with subplots_adjust and or tight_layout: setting constrained_layout==False.
  plt.tight_layout()

Saved sws result to: outputs/data/FACU_2009297_144044_SKS_sws_result.csv
Processing for event: NE81_2006360_122621_SKKS

/Users/eart0504/Documents/python/github_repositories/swspy/swspy/splitting/split.py:940: UserWarning: This figure was using constrained_layout==True, but that is incompatible with subplots_adjust and or tight_layout: setting constrained_layout==False.
  plt.tight_layout()

Saved sws result to: outputs/data/NE81_2006360_122621_SKKS_sws_result.csv
Processing for event: FACU_2009297_144044_SKS

/Users/eart0504/Documents/python/github_repositories/swspy/swspy/splitting/split.py:940: UserWarning: This figure was using constrained_layout==True, but that is incompatible with subplots_adjust and or tight_layout: setting constrained_layout==False.
  plt.tight_layout()

Saved sws result to: outputs/data/FACU_2009297_144044_SKS_sws_result.csv
Processing for event: RDM_2003174_121231_ScS

/Users/eart0504/Documents/python/github_repositories/swspy/swspy/splitting/split.py:940: UserWarning: This figure was using constrained_layout==True, but that is incompatible with subplots_adjust and or tight_layout: setting constrained_layout==False.
  plt.tight_layout()

Saved sws result to: outputs/data/RDM_2003174_121231_ScS_sws_result.csv
Processing for event: IRON_2009297_144044_SKS

/Users/eart0504/Documents/python/github_repositories/swspy/swspy/splitting/split.py:940: UserWarning: This figure was using constrained_layout==True, but that is incompatible with subplots_adjust and or tight_layout: setting constrained_layout==False.
  plt.tight_layout()

Saved sws result to: outputs/data/IRON_2009297_144044_SKS_sws_result.csv
Processing for event: K20A_2009003_223342_SKKS

/Users/eart0504/Documents/python/github_repositories/swspy/swspy/splitting/split.py:940: UserWarning: This figure was using constrained_layout==True, but that is incompatible with subplots_adjust and or tight_layout: setting constrained_layout==False.
  plt.tight_layout()

Saved sws result to: outputs/data/K20A_2009003_223342_SKKS_sws_result.csv
Processing for event: HUMO_2008321_170232_SKS

/Users/eart0504/Documents/python/github_repositories/swspy/swspy/splitting/split.py:940: UserWarning: This figure was using constrained_layout==True, but that is incompatible with subplots_adjust and or tight_layout: setting constrained_layout==False.
  plt.tight_layout()

Saved sws result to: outputs/data/HUMO_2008321_170232_SKS_sws_result.csv
Processing for event: K20A_2009003_223342_SKKS

/Users/eart0504/Documents/python/github_repositories/swspy/swspy/splitting/split.py:940: UserWarning: This figure was using constrained_layout==True, but that is incompatible with subplots_adjust and or tight_layout: setting constrained_layout==False.
  plt.tight_layout()

Saved sws result to: outputs/data/K20A_2009003_223342_SKKS_sws_result.csv
Processing for event: L24A_2009003_194355_SKKS

/Users/eart0504/Documents/python/github_repositories/swspy/swspy/splitting/split.py:940: UserWarning: This figure was using constrained_layout==True, but that is incompatible with subplots_adjust and or tight_layout: setting constrained_layout==False.
  plt.tight_layout()

Saved sws result to: outputs/data/L24A_2009003_194355_SKKS_sws_result.csv
Processing for event: L07A_2007256_094844_SKS

/Users/eart0504/Documents/python/github_repositories/swspy/swspy/splitting/split.py:940: UserWarning: This figure was using constrained_layout==True, but that is incompatible with subplots_adjust and or tight_layout: setting constrained_layout==False.
  plt.tight_layout()

Saved sws result to: outputs/data/L07A_2007256_094844_SKS_sws_result.csv
Processing for event: IRON_2009297_144044_SKS

/Users/eart0504/Documents/python/github_repositories/swspy/swspy/splitting/split.py:940: UserWarning: This figure was using constrained_layout==True, but that is incompatible with subplots_adjust and or tight_layout: setting constrained_layout==False.
  plt.tight_layout()

Saved sws result to: outputs/data/IRON_2009297_144044_SKS_sws_result.csv
Processing for event: COR_2008321_170232_SKS

/Users/eart0504/Documents/python/github_repositories/swspy/swspy/splitting/split.py:940: UserWarning: This figure was using constrained_layout==True, but that is incompatible with subplots_adjust and or tight_layout: setting constrained_layout==False.
  plt.tight_layout()

Saved sws result to: outputs/data/COR_2008321_170232_SKS_sws_result.csv
Processing for event: 116A_2006360_122621_SKKS

/Users/eart0504/Documents/python/github_repositories/swspy/swspy/splitting/split.py:940: UserWarning: This figure was using constrained_layout==True, but that is incompatible with subplots_adjust and or tight_layout: setting constrained_layout==False.
  plt.tight_layout()

Saved sws result to: outputs/data/116A_2006360_122621_SKKS_sws_result.csv
Processing for event: DAN_2003174_121231_ScS

/Users/eart0504/Documents/python/github_repositories/swspy/swspy/splitting/split.py:940: UserWarning: This figure was using constrained_layout==True, but that is incompatible with subplots_adjust and or tight_layout: setting constrained_layout==False.
  plt.tight_layout()

Saved sws result to: outputs/data/DAN_2003174_121231_ScS_sws_result.csv
Processing for event: 116A_2006360_122621_SKKS

/Users/eart0504/Documents/python/github_repositories/swspy/swspy/splitting/split.py:940: UserWarning: This figure was using constrained_layout==True, but that is incompatible with subplots_adjust and or tight_layout: setting constrained_layout==False.
  plt.tight_layout()

Saved sws result to: outputs/data/116A_2006360_122621_SKKS_sws_result.csv
Processing for event: RDM_2003174_121231_ScS

/Users/eart0504/Documents/python/github_repositories/swspy/swspy/splitting/split.py:940: UserWarning: This figure was using constrained_layout==True, but that is incompatible with subplots_adjust and or tight_layout: setting constrained_layout==False.
  plt.tight_layout()

Saved sws result to: outputs/data/RDM_2003174_121231_ScS_sws_result.csv
Processing for event: NE81_2006360_122621_SKKS

/Users/eart0504/Documents/python/github_repositories/swspy/swspy/splitting/split.py:940: UserWarning: This figure was using constrained_layout==True, but that is incompatible with subplots_adjust and or tight_layout: setting constrained_layout==False.
  plt.tight_layout()

Saved sws result to: outputs/data/NE81_2006360_122621_SKKS_sws_result.csv
Processing for event: NE81_2006360_122621_SKKS

/Users/eart0504/Documents/python/github_repositories/swspy/swspy/splitting/split.py:940: UserWarning: This figure was using constrained_layout==True, but that is incompatible with subplots_adjust and or tight_layout: setting constrained_layout==False.
  plt.tight_layout()

Saved sws result to: outputs/data/NE81_2006360_122621_SKKS_sws_result.csv
Processing for event: FACU_2009297_144044_SKS

/Users/eart0504/Documents/python/github_repositories/swspy/swspy/splitting/split.py:940: UserWarning: This figure was using constrained_layout==True, but that is incompatible with subplots_adjust and or tight_layout: setting constrained_layout==False.
  plt.tight_layout()

Saved sws result to: outputs/data/FACU_2009297_144044_SKS_sws_result.csv
Processing for event: RDM_2003174_121231_ScS

/Users/eart0504/Documents/python/github_repositories/swspy/swspy/splitting/split.py:940: UserWarning: This figure was using constrained_layout==True, but that is incompatible with subplots_adjust and or tight_layout: setting constrained_layout==False.
  plt.tight_layout()

Saved sws result to: outputs/data/RDM_2003174_121231_ScS_sws_result.csv
Processing for event: L07A_2007256_094844_SKS

/Users/eart0504/Documents/python/github_repositories/swspy/swspy/splitting/split.py:861: RuntimeWarning: More than 20 figures have been opened. Figures created through the pyplot interface (`matplotlib.pyplot.figure`) are retained until explicitly closed and may consume too much memory. (To control this warning, see the rcParam `figure.max_open_warning`).
  fig = plt.figure(constrained_layout=True, figsize=(8,6))

/Users/eart0504/Documents/python/github_repositories/swspy/swspy/splitting/split.py:940: UserWarning: This figure was using constrained_layout==True, but that is incompatible with subplots_adjust and or tight_layout: setting constrained_layout==False.
  plt.tight_layout()

Saved sws result to: outputs/data/L07A_2007256_094844_SKS_sws_result.csv
Processing for event: IRON_2009297_144044_SKS

/Users/eart0504/Documents/python/github_repositories/swspy/swspy/splitting/split.py:940: UserWarning: This figure was using constrained_layout==True, but that is incompatible with subplots_adjust and or tight_layout: setting constrained_layout==False.
  plt.tight_layout()

Saved sws result to: outputs/data/IRON_2009297_144044_SKS_sws_result.csv
Processing for event: HUMO_2008321_170232_SKS

/Users/eart0504/Documents/python/github_repositories/swspy/swspy/splitting/split.py:940: UserWarning: This figure was using constrained_layout==True, but that is incompatible with subplots_adjust and or tight_layout: setting constrained_layout==False.
  plt.tight_layout()

Saved sws result to: outputs/data/HUMO_2008321_170232_SKS_sws_result.csv
Processing for event: L24A_2009003_194355_SKKS

/Users/eart0504/Documents/python/github_repositories/swspy/swspy/splitting/split.py:940: UserWarning: This figure was using constrained_layout==True, but that is incompatible with subplots_adjust and or tight_layout: setting constrained_layout==False.
  plt.tight_layout()

Saved sws result to: outputs/data/L24A_2009003_194355_SKKS_sws_result.csv
Processing for event: HUMO_2008321_170232_SKS

/Users/eart0504/Documents/python/github_repositories/swspy/swspy/splitting/split.py:940: UserWarning: This figure was using constrained_layout==True, but that is incompatible with subplots_adjust and or tight_layout: setting constrained_layout==False.
  plt.tight_layout()

Saved sws result to: outputs/data/HUMO_2008321_170232_SKS_sws_result.csv
Processing for event: L24A_2009003_194355_SKKS

/Users/eart0504/Documents/python/github_repositories/swspy/swspy/splitting/split.py:940: UserWarning: This figure was using constrained_layout==True, but that is incompatible with subplots_adjust and or tight_layout: setting constrained_layout==False.
  plt.tight_layout()

Saved sws result to: outputs/data/L24A_2009003_194355_SKKS_sws_result.csv
Processing for event: K20A_2009003_223342_SKKS

/Users/eart0504/Documents/python/github_repositories/swspy/swspy/splitting/split.py:940: UserWarning: This figure was using constrained_layout==True, but that is incompatible with subplots_adjust and or tight_layout: setting constrained_layout==False.
  plt.tight_layout()

Saved sws result to: outputs/data/K20A_2009003_223342_SKKS_sws_result.csv
Processing for event: L07A_2007256_094844_SKS

/Users/eart0504/Documents/python/github_repositories/swspy/swspy/splitting/split.py:940: UserWarning: This figure was using constrained_layout==True, but that is incompatible with subplots_adjust and or tight_layout: setting constrained_layout==False.
  plt.tight_layout()

Saved sws result to: outputs/data/L07A_2007256_094844_SKS_sws_result.csv
Processing for event: COR_2008321_170232_SKS

/Users/eart0504/Documents/python/github_repositories/swspy/swspy/splitting/split.py:940: UserWarning: This figure was using constrained_layout==True, but that is incompatible with subplots_adjust and or tight_layout: setting constrained_layout==False.
  plt.tight_layout()

Saved sws result to: outputs/data/COR_2008321_170232_SKS_sws_result.csv
Processing for event: 116A_2006360_122621_SKKS

/Users/eart0504/Documents/python/github_repositories/swspy/swspy/splitting/split.py:940: UserWarning: This figure was using constrained_layout==True, but that is incompatible with subplots_adjust and or tight_layout: setting constrained_layout==False.
  plt.tight_layout()

Saved sws result to: outputs/data/116A_2006360_122621_SKKS_sws_result.csv
Processing for event: DAN_2003174_121231_ScS

/Users/eart0504/Documents/python/github_repositories/swspy/swspy/splitting/split.py:940: UserWarning: This figure was using constrained_layout==True, but that is incompatible with subplots_adjust and or tight_layout: setting constrained_layout==False.
  plt.tight_layout()

Saved sws result to: outputs/data/DAN_2003174_121231_ScS_sws_result.csv
Processing for event: DAN_2003174_121231_ScS

/Users/eart0504/Documents/python/github_repositories/swspy/swspy/splitting/split.py:940: UserWarning: This figure was using constrained_layout==True, but that is incompatible with subplots_adjust and or tight_layout: setting constrained_layout==False.
  plt.tight_layout()

Saved sws result to: outputs/data/DAN_2003174_121231_ScS_sws_result.csv
Processing for event: COR_2008321_170232_SKS

/Users/eart0504/Documents/python/github_repositories/swspy/swspy/splitting/split.py:940: UserWarning: This figure was using constrained_layout==True, but that is incompatible with subplots_adjust and or tight_layout: setting constrained_layout==False.
  plt.tight_layout()

Saved sws result to: outputs/data/COR_2008321_170232_SKS_sws_result.csv